Yarn changing mechanism for circular knitting machines



June 6,1939, s. E. THOMAS) 2,161,324

YARN CHANGING MECHANISM FOR CIRCULAR KNITTING MACHINES Filed Aug. 12, 1938 8' Sheets-Sheet 1 If G. I

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8 Sheets-Sheet s. E.'THOMAS Filed Aug. 12, 1958 June 6, 193 9.

YARN CHANGING MECHANISM FOR CIRCULAR KNITTING MACHINES ATTORNEYS.

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June 6, 1939. s, 1:, THOMAS 2,161,324

YARN CHANGING MECHANISM FOR CIRCULAR KNITTING MACHINES.

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' ,samuelfl Thomas,

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mhnmmlm l June 6, 1939. s. E. THOMAS 2,161,324

YARN CHANGING MECHANISH FOR CIRCULAR KNITTING MACHINES Filed Aug. 12, 1938 7 W8 Sheets-Sheet 4 Q mu QP'IIM g I I mn'lfl FIGJZ. J I 1 m 5 9 H 90 v Y 5 9J 105 a 20 I E15 11.21 m 91 5 T \H I 99 i I J HI I r JVW b m I; 1

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INVENTOR: Samuel E. Thomas,

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June 6, 1939'. E, T 2,161,324

YARN CHANGING MECHANISM FOR CIRCULAR KNITTING MACHINES 7 .Filed Aug. 12, 1938 & Sh ets-Sheet 5 H0. 1%. mm

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ATTORNEYS.

5. 1-: THOMAS Jun 6, 1939.

YARN CHANGI NG MECHANISM FQR CIRCULAR KNITTING MACHINES lff iled Aug. 12,- 1938 s Sheets-Sheet a O Q Q I t T O I flk O I U I I IN I I I INVENTOR: ,SamueZZIT/w I ATTORNEYS.

Patented June 6, 1939 YARN onANcmG MECHANISM FOR omenma KNITTING monnvns Samuel E. Thomas, Knoxville, Tenn. assignor to Holston Manufacturing Company, Knoxville, Tenn., a corporation of Tennessee Application August 12. 1938, semi No. 224.423

13 Claim.

5 to produce horizontal stripe effects in tubular fabrics with yarns of different kinds or colors.

Withusual types of yarn changing mechanisms,

loose yarn ends (pig tails) are left projecting from the outer side fabric tube at the points 10 'where the yarns are introduced into and withdrawn from the knitting. The elimination of these loose ends entails clipping'by hand which can be accomplished only upon reversal of the knitted fabric tube subsequent to the knitting, thereby adding very materially to production costs. Moreover, during the knitting, these loose uncontrolled ends are very apt to foul the needles, thereby causing press-offs with serious loss of time and protracted idling of the knitting machines-J The chief, aim of my invention is to obviate the above drawbacks, which objective I realize I in practice as hereinafter more fully explained,

throughprovision of means whereby the ends of 5 ingoing and outgoing yarns extending from the yarn eyes to a clamp embodied in the yarn changing [mechanism are caused to be taken and knitted by one of the two setsof the needles of the machines,preferably by the dial needles so as to be invisible at the front face of the fabric.

. In connection with yarn changing mechanism having the above attributes, it is a further aim vof my'invention to insure, through provision of simple and reliable means-such as also fully set 5- forth hereinafter, engagement of the withdrawn yarns by theclamp means afterseverance; to

insure, upon movement of a yarn feed to active position, against concurrent withdrawal of other yarns held by the clamp means; and to ease, as far aspossible; ready withdrawal of theyarns i from the clamp 'means with a view toward preventing chafing I 1 Other objects and attendant advantages will appear from the'following detailed description of the attached drawings, wherein Fig. I is a fragmentary view inend elevation of a circular rib knitting; machine embodying myimproved yarn changing mechanism. l

5 f II is apla'n section of the machine taken as'findicate d by the arrows II-II in Fig. I.

- Fig. III is a fragmentary view of the machine partly in front elevation and partly in axial section. I

Fig. IV is a fragmentary detail sectional view of the element which directly controls the yarn feeds. I

Fig. V is a detail plan sectional view on a larger scale taken as indicated by the arrows V-V in Fig. VI.

Fig. V1 is a view looking as indicated by the arrows VI-VI in Fig. I with the parts developed in a flat plane.

Figs. VII, VIII, IX, X and XI are views like Fig. VI showing successive steps of a yarn changing cycle.

Fig. XII is a detail sectional view on a larger scale taken as indicated by the arrows XIIXII in Fig. II. Fig. XIII is a fragmentary detail view partly in section and partly. in elevation showing means for severing and clamping the yarns.

Fig. IHV is a View like Fig. XIII with the clamping and severing means open ready to receive one of the yarns as it is withdrawn from action.

Figs. XV and XVI are fragmentaryviews respectively in plan and in perspective showing how the outgoing and ingoing yarns enter and leave the clamping means.

' Fig. XVII is a diagrammatic view showing the type ofhorizontal striped tubular work which can beproduced in the machine.

Fig. XVIII is a view showing the texture of the fabric within the confines of a dot-and-dash line rectangle XVIH in Fig. XVII.

Fig. XIX is a view in linear development showing the yarn fingers and in juxtaposition to the elements whereby they'are directlyact'uated.

I The knitting machine herein illustrated for convenience, of exemplifying my invention is generally of well known construction in that it has a circular bed plate [I which is supported by side frames 2 and 3. Stationarily mounted on the bed plate l; in coaxial relation thereto is a cylinder] with a series of vertical slots in its peripheral surface for retaining and guiding independent needles 5. k In turn coaxially arranged above the cylinder 4 is a circular dial 6 with radial grooves containing a series of independent horizontal needles I to cooperate with the cylinder needles in producing circular ribbed fabric in the usual way. In the present instance, the cylinder and dial needles are arranged to form a two to two rib effect. This arrangement is however immaterial insofar as my invention is concerned and may be changed or varied as desired. Journaled for rotation in a concentric annular groove 8 in the top of the bed plate I is a gear ring 9 to which is secured the carrier cylinder l for the cylinder needle knitting cams, not illustrated. The gear ring 9 is rotated in the direction of the arrow in Fig. 11 by an intermeshing pinion II at the inner end of the drive shaft l2 of the machine, which shaft is. suitably journaled in the side frame 3. needles I are actuated concurrently with the cylinder needles by suitable cams including a stitch cam H on a carrier disk I; which rotates with the cylinder needle cam carrier I0 and which is superposed axially upon the dial 6. The cam disk 13 is affixed to the lower end'of a shaft II depending from a plate Hi which is rotatively sustained in a bearing member I! supported by a pair of side standards it from the bed plate I of the machine. 7

The yarn changing mechanism with which the present invention is more especially concerned includes a plurality of guide fingers of which there are four in the present instance, designated 20-23, for directing individual yarns a, b, c, and d of different kinds or colorsgto the needles 5 and I of the knitting machine. The yarn fingers 20-23 are arranged side by side within a recess or gap 24 in a bracket 25 secured to-the rotating knitting cam carrier It; and have the capacity for independent up and down pivotal movement about a fulcrum pin 26 extending crosswise of said gap. Secured to an inward extension 121 of said bracket 25 is a needle latch guard 28 having a central recess 29 in which the free ends of the yarn fingers are accommodated when the latter are lowered to active position, 'see Figs. III and III. Individual helical tension springs 30 connected at opposite ends respectively to the fingers 20-23 and to a fixed anchorage 3| on the bracket 25 tend to urge said fingers upward to idle position against a stop ledge 32 afforded by-the spring anchorage, see Fig. XII. Adjacent the common fulcrum 26 the fingers are formed with cam projections such as instanced at 33 in Fig. XII, which lie in the path of lugs 34 on jacks 25 mounted in longitudinal peripheral grooves 26 of a selector drum 31. As shown, the drum 31 is keyed to a shaft 38 whereof the ends are Journaled in rear wardly extending bearing arms 39 on the. bracket 25. It will be noted that the lugs 34 are diversely positioned on the jacks 35 and that said jacks are arranged on the drum 3'! in accordance with the pattern which is to be produced in the work knitted by the machine. In order to make pattern changes possible, the jacks I! are removably mounted in the drum. 3! each with one of its ends engaged in a circumferential recess 40 in the inner face of a flange ll atone end of said drum, and each with a notch 42 at its opposite end engaged by a spring band 42 which encircles the opposite end of said drum. By intermittent rotativeshifts of the drum 31 in the direction of the arrow in Fig. 111, it will be seen that in accordance with their location, the lugs 14 of the jacks 25 will coact with the cam ends of the respective-guide fingers 20-22 and cause them to be individually lowered to active position. With the jack lugs 34 arranged as described, a previously active yarn finger will be freed to the action of its spring and swung to its idle position as a new finger is lowered-to take its place. Intermittent rotative shifts are imparted to .the drum 3! through picking of a ratchet wheel 45 on the drum shaft 38 by a pawl 48. The pawl 4G is pivotally connected to an arm'l'l fulcrumed at 48 on the bracket 25 and is yieldingly held in engagement with the teeth of the ratchet wheel by a spring 49 having teeth corresponding in The dialnumber to the jacks in the'drum 31. The picking of the drum I1 is governed by means including a pattern chain ill. with special high links 5|, said chain being trained about a sprocket wheel 52 v of a roller arm 00, by a cam projection on the gear ring 9 so that the ratchet wheel is picked once for each rotation of the machine. Overrunning of the sprocket wheel is prevented by a friction brake member 62 carried by an arm 63 secured by a set screw 65 to the stud I3. As a consequence of the picking of the ratchet wheel 55, a new link of the chain II is presented during each rotation of the machine beneath a roller.

66 at the lower end of a bar 61 guided for up and down movement in a bracket 68 attached to the edge of the bed plate I. the rod 61 is bent horizontally inward as at 61a for guidance in a clevis 69 at the top of the bracket 68 and then upward as at "b. At its upper end, the rod 61 carries an adjustable. screw stud I0 whereof the head engages the underside of a horizontal supporting member II whereto is secured, with capacity for in and out adjustment relative to the axis of the machine, a cam plate 12. The member II is confined to vertical movement in a guide bracket Ii-bolted to the top of the bed plate I. Normally, the cam plate 'I2is positioned ata level below the bottomend of the Ill beneath the roller 66 on the rod 81, it is elevated to the position shown in Fig. III, so that during a current rotation of the cam shell Ill, said pawl lever encounters the camand is actuated by it, with the result that the Jack drum 31 is rotativeLv shifted to effect an interchange of yarns. overthrow of the drum 2! is prevented by the action of an adjustable brake 15 (Figs. I and II) which is fulcrumed at I to one side of the bracket 25 and which clampingly engages the hub H of the ratchet wheel 48, at the corresponding end'of the drum shaft 38. A hook member 18 pivoted at I! on the bracket 68 coacts with a lateral projection of the-cam rest H to limit the upward movement of the latter.

Mounted on the dial needle cam carrier ii in contiguous relation to the yarn. changing mechanism is a yarn severing and clamping means comprehensively designated'in the drawings by As shown in Figs. II1I,-.

arewithdrawn from action and pushescthem inwardly between movable severing and clamping members 81, a and an outwardly-extending portion ll of the bracket 82 which affords complemental fixed severing and clamping edges. The movable severing blade 81 is attached to a slide which is subject to the downward pull of a spring ll confined to vertical movement'in an upstanding guide projection 92 on the bracket 82. At its upper end, the slide Ol has a pivotal connection N with the horizontal arm of a bell crank lever 25 fulcrumed at II to another proslot I86 (Figs. VI, XIII,

clamping member 88 so that the latter is actuated a,1e1,aa4 jection 81 on the bracket 82. The pendant arm of the bell crank lever 85 on the other hand is pivotally connected at 88 to one end of a lengthwise adjustable link 98 which, in turn, is pivotally connected at I88 to a horizontal arm I8I fulcrumed at I82 to the jack drum bracket 25, see Fig-II. As shown in Fig. XIV, the arm I 8| has a pendant end portion I83 adapted to engage the inner end of the vertically shiftable'cam plate 12 hereinbefore referred to. Projecting laterally from the slide 88 is a stud I 85 which engages a concurrently with said severing blade 81, The clampingmeans also includes a fixed clamp element in the form of a spring I81 with an out-.

\tendan't formation of a pinch interval to receive I the threads pushed into it by the booster 88.

'The thread booster 86 is also actuated from the vertically-shiftalile cam plate 12 whereof the inner edge is encountered by the pendant projection I88 of another finger I88 which is coaxially.

(the bristles normally bear down upon the dial needles 1. The pressure of. the brush II3 may be regulated by adjusting ,the arm II2 about the screw H5 by which it is secured to the edge of I the cam plate I3. .In order to better control the outgoing'and ingoing yarns incident to an interformed at one side with a smoothly-rounded guide change, the projection 88. of the bracket 82' is groove as shown at .II6 in Figs. VIII, IX and XVI, and the fin at one end with a guide notch as shown at II1 in'Fig. XVI.

The. operation-of my improved yarn changing mechanism is as follows: Y

Let it be assumedflthat the yarn finger 22 is in its lowered active position; and still feeding its yarn c to the needles 5 and 1 as shown in Fig.

VI.for the last course of the horizontal stripe C in Fig. XVII, and that the yarn finger 2| is about to be lowered to take its place. The interchange of these fingers is effected through elevation of the cam plate 12 into the path'of the pawl arm 41 with attendant shifting of the control drum 31 in the direction .indicated by the arrow in Fig. XII, so that the jack lug 340 is moved out of engagement with the cam projection 33 on the yarn finger 22 to allow lifting of the latter to idle position by its spring 38, while the lug 34b is moved into engagement with the cam projection 33 of the yarn finger 2| to lower said finger into active position against the pull of its spring 38-a1l as shown in Fig. VII. As a consequence of the interchange, the yarn b fed by the finger 2| is caught by a pair of cylinder needles 5b (Fig. VII), and

the yarn c lifted about a pair of cylinder needles 5c immediately rearward. of the needles 5b' as considered with regard to the direction of machine rotation. Due to encounter of the fingers IN and I82 with the cam plate 12 during interchange of the feeds 2I, 22, the yarn booster 88 is lifted and the movable knife blade 81 and clamp XIV) in the moving As the finger I82, which is in advance of the finger MI in the direction of machine rotation, passes beyond the cam plate 12, the yarn booster" 881- is moved inward from the positionof Fig. XIV to the position of Fig. XIII, and pushes the withdrawn yarn into the interval between the spring clamp I81 and the projection as shown in Fig. X,

and at the same time places said 'yarn in position to be cut and engaged respectively by the movable severing blade 81 and"the movable clamp member 88 as the latter snap downward from the position of Fig. XIV to that of Fig. XIII upon uent 0': a; cam plate'12- asillustrated in Fig. XI. The length or end 0' of the yarn 0 extending from the last fed cylinder needles 50 to the severing blade 81 (Fig. is caught by the brush H3 and thereby caused to be taken and knitted into the fabric by the dial needles. At the same time, the leading length or end b of the newly introduced yarn b extending from the first engaging cylinder needles 5b to the severing blade 81 is gradually withdrawn from beneath the spring clamp I81 as shown in Figs. VIIX and likewise pressed'downward by' the brush II8 so as to be caught and knitted into the fabric by the dial needles 1 together with the end' c' of the yarn c. As a result of this, it will be seen from Fig. XVIII, that the ends 0' and b' of the yarns cand b are relegated to the back face'of the fabric and do not therefore mar the appearance of the front face of the latter. so controlling the yarn ends and causing them tobe knitted into the fabric, I moreover efiectively preclude the possibility of press-offs and the disadvantages resulting therefrom. During withdrawal of the end I) of the newly introduced yarn b from beneath the fixed spring clamp I81, the

closed movable clamp member 88 operates as anauxiliary clamp to restrain the other yarns against being pulled with said newly introduced yarn from said spring clamp. While the interchange of yarns is rapid, there is an interval during which the old feed 22 is maintained in lowered position with the newly introduced feed to determine a definite amount of overlap of the yarns c and b during the knitting. This results from the extent and shaping of the curved edge portion of the camplate 12 extending between the points 12a, 12b. The amountof overlap may be increased by prolonging the extent of this curved portion of the cam edge, or decreased by shortening it. In being withdrawn from the knitting, the yarn c rides up the fin III and finally enters the notch III in the latter (Fig. XV) with the result that it is restrained against the possibility of being dragged back into the knitting bythe needles. The rounded notch H6 in the projection 89 of the bracket 82 on the other hand controls the end b, see Fig. XVI, in such manner that it is pulled out straight from beneath the spring clamp I81 with imposition thereupon of minimum restraint to the avoidance of injury through rupture or chafing. All other interchanges of yarns are effected in precisely the same manner as above explained, and as each new yarn is introduced, the

curved edge of the fin III acts to press the yarn inward toward the cylinder needles 5 to insure, its being. taken by said needles. By proper arrangement of the jack lugs in the drum, as shown in Fig. XIX, and allocation of the high links 58 on the chain 5| as shown in Fig. I, it is possible in predetermine with yarns a, b, c, d, of different kinds or colors, in the tubular fabric produced by the machine patterns such as exemplified in Fig. xvn characterised by horizontal stripes A, B, C, and D of varying depth.

It is of course to be understood that my lnvenf commodation within the gap 2 in the bracket 25. It is also to be understood that the number of selector drums 31 may have more or less peripheral grooves, and the ratchet wheel 45 more or less teeth than shown in the drawings. The number of grooves in the drum may moreover be different from that of the teeth on the ratchet wheel. Preferably, however, I employ a drum and a ratchet wheel in which the grooves and the teeth correspond in number as exemplified in the drawings. For the purposes of economy and convenience, I preferably make all the drum -lacks 35 initially with eight lug projections separated by slits or saw cuts, and break out such lugs as are not -needed according to'the stripe pattern which is to be produced.

Having thus described my invention, I claim:

1. In a circular knitting machine having two sets of opposing needles and means to actuate them; yarn chan'ging mechanism comprising a multiplicity of independently-movable yarn feeds,

actuating means for selectively'interchanging the feeds with predetermination of a definite overlap in the knitting of the threads, means for severing and clamping the yarns as they are withdrawn from action, and means operative to cause the leading and trailing ends respectively of the ingoing and outgoing yarns extending from the clamp means to the interchanged feeds to be knitted into the fabric by one set of the needles.

,2. In a circular knitting machine having two sets of opposing needles and means to actuate them; yarn changing mechanism comprising a multiplicity of independently-movable yam feeds, actuating means for selectively interchanging the feeds with predetermination of a definite overlap in the knitting of the threads, means for severing and clamping the yarns as they are withdrawn from action, means operative to cause the leading and trailing ends respectively of the ingoing and outgoing yarns extending from the clamp means to the interchanged feeds to be knitted into the fabric by one set of the needles, and means to prevent withdrawal of the yarns from the clamp except for the yarn of the substituted feed.

3. In a circular knitting machine having opposing cylinder and dial needles and means to actuate them; yarn changing mechanism comprising a multiplicity of independently movable yarn feeds,

' means for selectively interchanging the feeds with predetermination of a definite overlap in the knitting of the threads, means for severing and clamping the yarns as they are withdrawn from action, and means operative to cause the leading and trailing ends respectively of the ingoing and outgoing yarns extending from the clamp means to the interchanged feeds to be knitted into the fabric by the dial needles.

4. Yarn changing mechanism according to claim 1, in which the feeds are pivoted side by sidev on a common axis, and in which the actuating means includes a drum having variantly arranged circumferential lug projections to cooperate with cam projections on the feeds, and means for intermittently rotating the drum.

5. Yarn changing mechanism according to claim 1, in which the feeds are pivoted side by side on a common axis, and in which the actuating oneness Z means includes a drum having a series of longitudinal slots in its circumference, jacks removably engaged in the slots and having outward lug proiections variantly arranged along their lengths to coact with cam projections on the feeds, and means for intermittently rotating the drum.

6. Yarn changing mechanism according to claim 1, in which the feeds are pivoted side by side on a common axis, and in which the actuating means includes a drum having variantly arranged circumferential projections to cooperate with cam projections on the feeds, a ratchet wheel connected to the drum, a pawlto cooperate with the ratchet, a pawl arm, and pattern control means for actuating the pawl arm at predetermined intervals to cause intermittent rotative shifts of the drum.

7. In a circular knitting machine having a stationary needle cylinder, a coaxial stationary needle dial, and knitting cam carrier means rotative about the axis of the cylinder and dial, yarn changing mechanism supported by said carrier means and comprising a multiplicity of independently movable yarn feeds, means supported by the carrier means for selectively interchanging the yarn feeds with predetermination of a definite overlap'in the knitting of the threads,

from action; and means operative to cause the leading and trailing ends respectively of the ingoing and outgoing yarns extending from the clamp means to the interchanged feeds to be knitted into the fabric by the dial needles.

8. Yarn .changing mechanism according to claim 7, in which the feeds are pivoted side by side on a common horizontal axis, and in which the actuating means includes a horizontal drum with variantly arranged circumferential projections to cooperate with cam projectionson the feeds, a ratchet wheel attached to the drum, a pawl to cooperate with the ratchet, a pivoted arm carrying the pawl, a cam plate normally out of the range of the pawl arm, a pattern chain with interchangeable high links adapted to cause shifting of the cam plate into the path of the pawl arm and thereby efi'ect rocking of the drum, and

means for intermittently rotating a sprocket about which the chain is trained.

9. In a circular knitting machine having a stationary needle cylinder, a coaxial stationary needle dial, and knitting cam carrier means ro-, tative about the axis of the cylinder and dial; yarn changing means supported by said carrier means and including a multiplicity of independently-movable feeds, control means supported by the carrier means for selectively interchanging theyarn feeds with predetermination of a definite overlap in the knitting of the threads, yarn severing and clamping means mounted on the carrier means and including stationary and movable shearing members, a fixed yielding spring clamp, an auxiliary clamp with a movable clamp member, a pivoted actuating finger connected to the movable shearing member and the movable member of the auxiliary clamp and operative to move said members to open position to receive the withdrawn yarn, means to afterwards close said movable members to sever and hold the withdrawn yarn, a booster for placing the withdrawn yarn into the spring clamp during the interval of opening of the severing means and the auxiliary clamp, a pivoted finger for actuating the booster, and a cam plate normally out of the path of the two fingers; and means for moving the cam plate into the path of said fingers to claim 9, wherein the fixed clamp member has a guide groove for controlling the end of the newly introduced yarn to insure withdrawal of its trailing end in a straight line from the spring clamp.

12. Yarn changing mechanism according to 'claim 9, wherein the needle cam carrler means" provides an outwardly-extending inclined fin operative to urge the ingoing yarns toward the cylinder needles.

13. Yarn changing mechanism according to claim 9, wherein the needle cam carrier means provides an outwardly-extending inclined fin .operative to urge the ingoing yarns toward the cylinder needles, and wherein said fin is provided with a notch at its upper end for receiving and controlling the yarns incident to their withdrawal from the knitting.

SAMUEL E. THOMAS. 

